1. Field of the Invention
This invention relates to protective liquid containment systems in general, and more specifically to a secondary or back up containment apparatus for hazardous liquid chemicals.
2. Description of the Prior Art
Various methods are in use today to protect against inadvertent leakage of hazardous chemicals from their respective containers. Most of the protective packaging is focused on small breakable bottles wherein the main objective is prevention of damage to the container. Many of the hazardous chemicals used today in various industries are transported and stored in conventional fifty-five gallon drums, and leakage of the contents with subsequent contamination of the surrounding area has become a serious problem. A patent search was therefore conducted to uncover past art devices designed to prevent the distribution of hazardous chemicals originating from ruptures in large or heavy containers. The search was conducted in the following classes and subclasses:
150/52R, and 52F.
Patents considered pertinent to my invention include the following:
U.S. Pat. No. 1,460,461, issued to West on July 3, 1923, discloses a sanitary and temperature insulating jacket for milk cans.
Frank was granted U.S. Pat. No. 2,426,475, on Aug. 26, 1947, for a cooling jacket for milk cans.
On Mar. 8, 1949, Benson was issued U.S. Pat. No. 2,464,069, for a shock absorbent bottle carrier designed primarily to protect the glass bottle from breakage.
U.S. Pat. No. 2,522,381, was granted to Kramer on Sept. 12, 1950, for a temperature retaining cover for bottles.
The West and Frank devices are designed to provide cooling measures for milk cans and are not specifically concerned with preventing leakage. These two devices also show outer jackets having opened bottom surfaces which are connected to the containers by girding bands or sealing rings. Girding bands have not proven to be an effective sealing means when the exterior wall of the container contains dents or seams. Any irregularities in the smooth cylindrical exterior wall of the container against which the girding band is attached would allow seepage of spilled contents. The Frank device contains a supportive base affixed with an outer annular groove into which the bottom edge of the jacket is inserted and secured with a sealing ring. This sealing system is also adversely affected by dents in the wall of the annular groove as well as sand or other debris contained within the bottom of the groove. Both interfere with a sealing system which depends on a flush and even seal against the exterior wall of the container. The outward extending projection of the annular groove leaves it prone to damage caused by blows or impacts against other objects which could cause the afore mentioned dents and irregularities in the wall of the annular groove. The widespread practice of rolling large fifty-five gallon drums on the bottom edge to move them short distances would eliminate the use on the Frank patent due to the susceptibility of the annular groove to damage.
The Karmer patent shows an insulated cover designed to retain the heat of the contents of the container. This device would be unsuitable utilized as a protective liner to cover large and heavy drums in that the narrow bottom rim of the drum would be resting on the cover. The drum rim could cut into the cover as the drum is rolled on the bottom edge making perforations in the cover. This would allow leakage of the drum contents should a rupture occur.
Although the Benson patent appears to be most relevant to my invention, the design of the device is limited to small glass bottles. An effect similar to that occurring with the afore mentioned Kramer device would result if the Benson carrier were adapted to large or heavy drums. The result would be the same damage to the carrier previously mentioned from the bottom rim of the drum when it is rolled on edge.
Although not found in the patent search, large drums of chemicals are sometimes stored in open topped liquid tight containers. These secondary or back up drum containers have rigid side walls which require the chemical containing drum to be lifted above the open top of the back up container and be lowered inside. Since drums full of chemicals are very heavy, mechanical hoists are needed for the lifting process.
To my knowledge, the foregoing patents represent devices most pertinent to my invention. I did not consider any of the examined patented devices suitable for use with heavy or large drums and similar containers.